[ceph-users] Is it safe to mix Octopus and Pacific mons?

Hello My attempt to upgrade from Octopus to Pacific ran into issues, and I currently have one 16.2.4 mon and two 15.2.12 mons. Is this safe to run the cluster like this or should I shut down the 16.2.4 mon until I figure out what to do next with the upgrade? Thanks, Vlad